There is a cake shop after the flight check in counter @ the airport. I normally bought it from there. Even early flight (leaving at 8 in the morning), they have pandan leave cake as well as some dessert using coconut milk but of course not as much choice as in the afternoon.
We will buy at least one for the kids since they all love it.
They will keep the cake in the fridge...make sure you keep the cake at room temp for 1-2 hrs before you serve it....it will taste better.